Mixtures of discrete carbon nanotubes

ABSTRACT

Dry liquid concentrates allow carbon nanotubes to be dispersed in rubber formulations under standard rubber processing conditions. The incorporation of carbon nanotubes can enhance the physical properties of the resulting rubber material in many ways, including creating a more resilient rubber which resists abrasion, tearing, and chipping.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.16/157,499 filed on Oct. 11, 2018 which claims the benefit of U.S.Provisional Application Ser. No. 62/571,026 filed Oct. 11, 2017.

FIELD OF INVENTION

The present invention is directed to novel carbon nanotube compositionsand formulations thereof, such as with oils and rubbers.

BACKGROUND AND SUMMARY

Carbon nanotubes can be classified by the number of walls in the tube,single-wall, double wall, and multiwall. Carbon nanotubes are currentlymanufactured as agglomerated nanotube balls, bundles, or forestsattached to substrates. Use of carbon nanotubes as a reinforcing agentin elastomeric compositions, polymer composites, and rubber compositesis an area in which carbon nanotubes have been shown to have significantutility. The utilization of carbon nanotubes in these applications waspreviously hampered due to the general inability to reliably produceindividualized carbon nanotubes and the ability to disperse theindividualized carbon nanotubes in a matrix. Previous research byBosnyak et al., disclosed in various patent applications (e.g., US2012-0183770 A1 and US 2011-0294013 A1), have made discrete carbonnanotubes through judicious and substantially simultaneous use ofoxidation and shear forces, thereby oxidizing both the inner and outersurface of the nanotubes, typically to about the same oxidation level onthe inner and outer surfaces, resulting in individual or discrete tubes.

The present invention differs from those earlier Bosnyak et al.applications and disclosures. The present invention describes acomposition of carbon nanotubes and manufacturing techniques which allowthe creation of dry liquid concentrates which may be incorporated intorubber compositions in order to efficiently create rubber compositeswith dispersed, individualized, discrete carbon nanotubes. These newcompositions and manufacturing techniques are useful in manyapplications, including dry liquid concentrates, which can then be usedas an additive in the compounding and formulation of rubber compositefor the improvement of mechanical, electrical and thermal properties.

The discussed carbon nanotubes may be single, double, or multi-wallcarbon nanotubes. The carbon nanotubes may or may not be oxidized on theinterior and/or exterior surface and are not limited to any aspectratio.

The carbon nanotubes discussed herein may be discrete, individualizedcarbon nanotubes having targeted, or selective, oxidation levels and/orcontent on the exterior and/or interior of the tube walls. Such carbonnanotubes may have little to no inner tube surface oxidation, ordiffering amounts and/or types of oxidation between the tubes' inner andouter surfaces. Such tubes are useful in many applications, includingplasticizers, which can then be used as an additive in compounding andformulation of rubber, elastomeric, thermoplastic and thermosetcomposite for improvement of mechanical, electrical and thermalproperties.

The carbon nanotubes discussed herein may comprise an interior andexterior surface, each surface comprising an interior surface oxidizedspecies content and an exterior surface oxidized species content,wherein the interior surface oxidized species content differs from theexterior surface oxidized species content by at least 20%, and as highas 100%, preferably wherein the interior surface oxidized speciescontent is less than the exterior surface oxidized species content.

The interior surface oxidized species content can be up to 3 weightpercent relative to carbon nanotube weight, preferably from about 0.01to about 3 weight percent relative to carbon nanotube weight, morepreferably from about 0.01 to about 2, most preferably from about 0.01to about 1. Especially preferred interior surface oxidized speciescontent is from zero to about 0.01 weight percent relative to carbonnanotube weight.

The exterior surface oxidized species content can be from about 1 toabout 6 weight percent relative to carbon nanotube weight, preferablyfrom about 1 to about 4, more preferably from about 1 to about 2 weightpercent relative to carbon nanotube weight. This is determined bycomparing the exterior oxidized species content for a given plurality ofnanotubes against the total weight of that plurality of nanotubes.

The interior and exterior surface oxidized species content totals can befrom about 1 to about 9 weight percent relative to carbon nanotubeweight.

The carbon nanotubes discussed herein may additionally or alternativelycomprise an interior and exterior surface, each surface comprising aninterior surface and an exterior surface oxidized species content,wherein the interior surface oxidized species content comprises fromabout 0.01 to less than about 1 percent relative to carbon nanotubeweight and the exterior surface oxidized species content comprises morethan about 1 to about 3 percent relative to carbon nanotube weight.

The carbon nanotubes discussed herein may comprise a plurality of openended tubes. The carbon nanotubes of any composition or embodimentdescribed herein are especially preferred wherein the inner and outersurface oxidation difference is at least about 0.2 weight percent.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows an exemplary constrained tear test sample.

FIG. 2 shows a TEM image of a sample of NBR Formulation 72B.

FIG. 3 shows an HNBR sample containing carbon nanotubes dispersed fromDLC without carbon black.

FIG. 4 shows an HNBR sample containing 50 phr carbon black withoutcarbon nanotubes.

FIG. 5 shows an HNBR sample containing 3 phr carbon nanotubes and 50 phrcarbon black.

FIG. 6 shows an HNBR sample containing MR dispersed via DLC.

FIG. 7 shows an HNBR sample containing CNTs dispersed via DLC.

FIGS. 8a and 8b show a HNBR samples containing dry CNTs.

FIG. 9 shows a sketch of a B.F. Goodrich cut and chip testing device.

FIG. 10 shows a graph of compression set test results.

FIG. 11 shows a graph of constrained tear test results.

FIG. 12 shows a graph of Die C tear strength results.

FIG. 13 shows a graph of constrained tear test data.

FIG. 14 shows a graph of cut and chip test results.

FIG. 15 shows particle size distribution data from the High Shear v.Bundled v. Mixture of High Shear and Bundled Example below.

DETAILED DESCRIPTION

Dry Liquid Concentrates

One embodiment of the present invention is a dry liquid concentrate(“DLC”) comprising carbon nanotubes and rubber processing oils thatdisperses under typical compounding conditions into a rubber compound.The carbon nanotubes in a DLC are not dispersed but will disperse intorubber compounds and may also be useful for dispersing carbon nanotubesin other processing operations due to the method's lower energyrequirements.

One aspect of the disclosed invention is that the carbon nanotubes inthe DLC composition may be as-manufactured raw carbon nanotubes and donot need to be disentangled from their raw state prior to being formedinto a DLC. Once in the DLC form, the carbon nanotubescan bedisentangled and dispersed in the final rubber formulation.

Raw CNTs can be used to create a dry-liquid concentrate and providebenefits in the final rubber compound. This surprising and unexpectedresult reduces manufacturing costs and difficulty. Previously usedmethods of disentangling carbon nanotubes are more energy intensive andmore costly. The disclosed method maintains the same physical propertyimprovements. The resulting composition also maintains the sameenvironmental health and safety (“EH&S”) improvements as the previousmethods of manufacturing a dry liquid concentrate which required carbonnanotubes to be disentangled prior to being incorporated into the DLC.

One exemplary method of creating the disclosed DLC involves mixing raw,as-manufactured carbon nanotubes in de-ionized water and heating to 65degrees Celsius while stirring with overhead stirring and a high shearblade. Oil is added to the water/CNT solution upon reaching the desiredtemperature and the solution is allowed to mix until phase separationoccurs. Once phase separation occurs, the carbon nanotubes will becontained in the oil layer. When the carbon nanotube/oil layer separatesfrom the water layer, the water may be filtered out and the resultingoil/CNT composition may be dried in an oven.

The concentration of CNTs in de-ionized water should not exceed about1.8% by weight. Surprisingly, the overhead mixing used may be of a lowershear force than is traditionally required to disperse or disentanglethe CNTs within the water or oil solution.

Embodiments of the DLC composition may comprise as little as 5% byweight, or as little as 10% by weight, or as little as 15% by weightcarbon nanotubes. Preferred embodiments of the disclosed DLC compositioncomprise about 20% by weight of carbon nanotubes. Embodiments of the DLCcomposition may comprise as much as 25% by weight, as much as 30% byweight, as much as 35% by weight, as much as 40% by weight, as much as50% by weight of carbon nanotubes. The remainder of the DLC compositionis substantially composed of rubber processing oils. The ratio of carbonnanotubes to oil impacts the resulting product and its properties.Rubber process oil may include, for example, TOTM oil, TP-95, HyPrene100 naphthenic oil, castor oil, carnauba wax, curing co-agents, and/orsebacates.

Acid and Multi-Wall Carbon Nanotube (CNT) Loading

CNT is usually shipped in bulk sea containers and unloaded at theprocessing site. Boxes or containers of CNT bags often have innerplastic liners to facilitate the prevention of CNTs escaping. The boxesare typically unloaded in a High efficiency particulate air (HEPA)filtered closed environment and bags may be passed through a wallopening to a bag emptying room.

In the bag emptying room, to prevent CNT exposure, CNT bags aretypically loaded into an air tight hopper and accessed by personnel fromoutside the hopper by means of gloves, similar to a sand/bead blastingglove box. The hopper is usually equipped with an external HEPA vacuumthat can be turned on while the CNT bags are loaded into the hopper. TheHEPA filter can then be turned off before the bags are opened inside thehopper to prevent excessive amounts of CNT from entering the filter. Adouble diaphragm powder pump may be conveniently used to load the CNTfrom the hopper to the reactor and a Coriolis mass meter may be employedto ensure proper acid loading. The acid is typically at a temperature ofbetween 95 and 110° C.

Alternatively, CNT loading and packaging for large scale production maybe accomplished by receiving CNT in, for example, cone bottom stainlesssteel containers or other reusable containers equipped with splitbutterfly valves. The container then can be attached to a loading systemwith mating butterfly valve and intermediate extraction zone that isvacuum evacuated or exhausted between valves to insure <0.7 microgram/m³exposure. This stream may then be filtered through a HEPA filtrationsystem.

General Process to Produce Discrete Carbon Nanotubes Having TargetedOxidation

A mixture of 0.5% to 5% carbon nanotubes, preferably 3%, by weight isprepared with CNano grade Flotube 9000 carbon nanotubes and 65% nitricacid. While stirring, the acid and carbon nanotube mixture is heated to70 to 90 degrees C. for 2 to 4 hours. The formed oxidized carbonnanotubes are then isolated from the acid mixture. Several methods canbe used to isolate the oxidized carbon nanotubes, including but notlimited to centrifugation, filtration, mechanical expression, decantingand other solid-liquid separation techniques. The residual acid is thenremoved by washing the oxidized carbon nanotubes with an aqueous mediumsuch as water, preferably deionized water, to a pH of 3 to 4. The carbonnanotubes are then suspended in water at a concentration of 0.5% to 4%,preferably 1.5% by weight. The solution is subjected to intenselydisruptive forces generated by shear (turbulent) and/or cavitation withprocess equipment capable of producing energy densities of 106 to 108Joules/m³. Equipment that meet this specification includes but is notlimited to ultrasonicators, cavitators, mechanical homogenizers,pressure homogenizers and microfluidizers (Table 1). One suchhomogenizer is shown in U.S. Pat. No. 756,953, the disclosure of whichis incorporated herein by reference. Other shearing type equipment thatmay be useful include, for example, tangential type mixer, intermeshingtype mixer, 2 roll mill, calendaring mill, and a screw type extruderlike a Haake or Brabender extruder, or combination thereof. After shearprocessing, the oxidized carbon nanotubes are discrete andindividualized carbon nanotubes. Typically, based on a given startingamount of entangled as-received and as-made carbon nanotubes, aplurality of discrete oxidized carbon nanotubes results from thisprocess, preferably at least about 60%, more preferably at least about75%, most preferably at least about 95% and as high as 100%, with theminority of the tubes, usually the vast minority of the tubes remainingentangled, or not fully individualized.

Another illustrative process for producing discrete carbon nanotubesfollows: A mixture of 0.5% to 5% carbon nanotubes, preferably 3%, byweight is prepared with CNano Flotube 9000 grade carbon nanotubes and anacid mixture that consists of 3 parts by weight of sulfuric acid (97%sulfuric acid and 3% water) and 1 part by weight of nitric acid (65-70percent nitric acid). The mixture is held at room temperature whilestirring for 3-4 hours. The formed oxidized carbon nanotubes are thenisolated from the acid mixture. Several methods can be used to isolatethe oxidized carbon nanotubes, including but not limited tocentrifugation, filtration, mechanical expression, decanting and othersolid-liquid separation techniques. The acid is then removed by washingthe oxidized carbon nanotubes with an aqueous medium, such as water,preferably deionized water, to a pH of 3 to 4. The oxidized carbonnanotubes are then suspended in water at a concentration of 0.5% to 4%,preferably 1.5% by weight. The solution is subjected to intenselydisruptive forces generated by shear (turbulent) and/or cavitation withprocess equipment capable of producing energy densities of 10⁶ to 10⁸Joules/m³. Equipment that meet this specification includes but is notlimited to ultrasonicators, cavitators mechanical homogenizers, pressurehomogenizers and microfluidizers (Table 1). After shear and/orcavitation processing, the oxidized carbon nanotubes become oxidized,discrete carbon nanotubes. Typically, based on a given starting amountof entangled as-received and as-made carbon nanotubes, a plurality ofdiscrete oxidized carbon nanotubes results from this process, preferablyat least about 60%, more preferably at least about 75%, most preferablyat least about 95% and as high as 100%, with the minority of the tubes,usually the vast minority of the tubes remaining entangled, or not fullyindividualized.

Example 1: Entangled Oxidized as MWCNT—3 Hour (oMWCNT-3)

One hundred milliliters of >64% nitric acid is heated to 85 degrees C.To the acid, 3 grams of as-received, multi-walled carbon nanotubes(C9000, CNano Technology) are added. The as-received tubes have themorphology of entangled balls of wool. The mixture of acid and carbonnanotubes are mixed while the solution is kept at 85 degrees for 3 hoursand is labeled “oMWCNT-3”. At the end of the reaction period, theoMWCNT-3 are filtered to remove the acid and washed with reverse osmosis(RO) water to pH of 3-4. After acid treatment, the carbon nanotubes arestill entangled balls. The tubes are dried at 60° C. to constant weight.

Example 2: Entangled Oxidized as MWCNT—6 Hour (oMWCNT-6)

One hundred milliliters of >64% nitric acid is heated to 85 degrees C.To the acid, 3 grams of as-received, multi-walled carbon nanotubes(C9000, CNano Technology) are added. The as-received tubes have themorphology of entangled balls of wool. The mixture of acid and carbonnanotubes are mixed while the solution is kept at 85 degrees for 6 hoursand is labeled “oMWCNT-6”. At the end of the reaction period, theoMWCNT-6 are filtered to remove the acid and washed with reverse osmosis(RO) water to pH of 3-4. After acid treatment, the carbon nanotubes arestill entangled balls. The tubes are dried at 60° C. to constant weight.

Example 3: Discrete Carbon Nanotube—Oxidize Outermost Wall (Out-dMWCNT)

In a vessel, 922 kilograms of 64% nitric acid is heated to 83° C. To theacid, 20 kilograms of as received, multi-walled carbon nanotubes (C9000,CNano Technology) is added. The mixture is mixed and kept at 83° C. for3 hours. After the 3 hours, the acid is removed by filtration and thecarbon nanotubes washed with RO water to pH of 3-4. After acidtreatment, the carbon nanotubes are still entangled balls with few openends. While the outside of the tube is oxidized forming a variety ofoxidized species, the inside of the nanotubes have little exposure toacid and therefore little oxidization. The oxidized carbon nanotubes arethen suspended in RO water at a concentration of 1.5% by weight. The ROwater and oxidized tangled nanotubes solution is subjected to intenselydisruptive forces generated by shear (turbulent) and/or cavitation withprocess equipment capable of producing energy densities of 10⁶ to 10⁸Joules/m³. The resulting sample is labeled “out-dMWCNT” which representsouter wall oxidized and “d” as discrete. Equipment that meet this shearincludes but is not limited to ultrasonicators, cavitators, mechanicalhomogenizers, pressure homogenizers, and microfluidizers (Table 1). Itis believed that the shear and/or cavitation processing detangles anddiscretizes the oxidized carbon nanotubes through mechanical means thatresult in tube breaking and opening of the ends due to breakageparticularly at defects in the CNT structure which is normally a 6member carbon rings. Defects happen at places in the tube which are not6 member carbon rings. As this is done in water, no oxidation occurs inthe interior surface of the discrete carbon nanotubes.

Example 4: Discrete Carbon Nanotube—Oxidized Outer and Inner Wall(Out/In-dMWCNT)

To oxidize the interior of the discrete carbon nanotubes, 3 grams of theout-dMWCNT is added to 64% nitric acid heated to 85° C. The solution ismixed and kept at temperature for 3 hours. During this time, the nitricacid oxidizes the interior surface of the carbon nanotubes. At the endof 3 hours, the tubes are filtered to remove the acid and then washed topH of 3-4 with RO water. This sample is labeled “out/in-dMWCNT”representing both outer and inner wall oxidation and “d” as discrete.

Oxidation of the samples of carbon nanotubes is determined using athermogravimetric analysis method. In this example, a TA Instruments Q50Thermogravimetric Analyzer (TGA) is used. Samples of dried carbonnanotubes are ground using a vibration ball mill. Into a tared platinumpan of the TGA, 7-15 mg of ground carbon nanotubes are added. Themeasurement protocol is as follows. In a nitrogen environment, thetemperature is ramped from room temperature up to 100° C. at a rate of10° C. per minute and held at this temperature for 45 minutes to allowfor the removal of residual water. Next the temperature is increased to700° C. at a rate of 5° C. per minute. During this process the weightpercent change is recorded as a function of temperature and time. Allvalues are normalized for any change associated with residual waterremoval during the 100° C. isotherm. The percent of oxygen by weight ofcarbon nanotubes (% Ox) is determined by subtracting the percent weightchange at 600° C. from the percent weight change at 200° C.

A comparative table (Table 2 below) shows the levels of oxidation ofdifferent batches of carbon nanotubes that have been oxidized eitherjust on the outside (Batch 1, Batch 2, and Batch 3), or on both theoutside and inside (Batch 4). Batch 1 (oMWCNT-3 as made in Example 1above) is a batch of entangled carbon nanotubes that are oxidized on theoutside only when the batch is still in an entangled form (Table 2,first column). Batch 2 (oMWCNT-6 as made in Example 2 above) is also abatch of entangled carbon nanotubes that are oxidized on the outsideonly when the batch is still in an entangled form (Table 2, secondcolumn). The average percent oxidation of Batch 1 (2.04% Ox) and Batch 2(2.06% Ox) are essentially the same. Since the difference between Batch1 (three hour exposure to acid) and Batch 2 (six hour exposure to acid)is that the carbon nanotubes were exposed to acid for twice as long atime in Batch 2, this indicates that additional exposure to acid doesnot increase the amount of oxidation on the surface of the carbonnanotubes.

Batch 3 (Out-dMWCNT as made in Example 3 above) is a batch of entangledcarbon nanotubes that were oxidized on the outside only when the batchwas still in an entangled form (Table 2, third column). Batch 3 was thenbeen made into a discrete batch of carbon nanotubes without any furtheroxidation. Batch 3 serves as a control sample for the effects onoxidation of rendering entangled carbon nanotubes into discretenanotubes. Batch 3 shows essentially the same average oxidation level(1.99% Ox) as Batch 1 and Batch 2. Therefore, Batch 3 shows thatdetangling the carbon nanotubes and making them discrete in water opensthe ends of the tubes without oxidizing the interior.

Finally, Batch 4 (Out/In-dMWCNT as made in this Example 4 herein) is abatch of entangled carbon nanotubes that are oxidized on the outsidewhen the batch is still in an entangled form, and then oxidized againafter the batch has then been made into a discrete batch of carbonnanotubes (Table 2, fourth column). Because the discrete carbonnanotubes are open ended, in Batch 4 acid enters the interior of thetubes and oxidizes the inner surface. Batch 4 shows a significantlyelevated level of average oxidation (2.39% Ox) compared to Batch 1,Batch 2 and Batch 3. The significant elevation in the average oxidationlevel in Batch 4 represents the additional oxidation of the carbonnanotubes on their inner surface. Thus, the average oxidation level forBatch 4 (2.39% Ox) is about 20% higher than the average oxidation levelsof Batch 3 (1.99% Ox). In Table 2 below, the average value of theoxidation is shown in replicate for the four batches of tubes. Thepercent oxidation is within the standard deviation for Batch 1, Batch 2and Batch 3.

TABLE 1 Energy Density Homogenizer Type Flow Regime (J-m⁻³) Stirredtanks turbulent inertial, turbulent viscous, laminar 10³-10⁶ viscousColloid mil laminar viscous, turbulent viscous 10³-10⁸ Toothed - discdisperser turbulent viscous 10³-10⁸ High pressure homogenizer turbulentinertial, turbulent viscous, 10⁶-10⁸ cavitation inertial, laminarviscous Ultrasonic probe cavitation inertial 10⁶-10⁸ Ultrasonic jetcavitation inertial 10⁶-10⁸ Microfluidization turbulent inertial,turbulent viscous 10⁶-10⁸ Membrane and microchannel Injectionspontaneous transformation based Low 10³Excerpted from Engineering Aspects of Food Emulsification andHomogenization, ed. M Rayner and P. Dejmek, CRC Press, New York 2015.

TABLE 2 Percent oxidation by weight of carbon nanotubes. Batch 3: Batch4: Difference *% difference Batch 1: Batch 2: Out- Out/In- in % Ox in %Ox oMWCNT-3 oMWCNT-6 dMWCNT dMWCNT (Batch 4 − (Batch 4 v % Ox % Ox % Ox% Ox Batch 3) Batch 3) 1.92 1.94 2.067 2.42 0.353 17% 2.01 2.18 1.8972.40 0.503 26.5%  2.18 NM 2.12 2.36 0.24  11% 2.05 NM 1.85 NM n/a n/aAverage 2.04 2.06 1.99 2.39 0.4  20% St. Dev. 0.108  0.169 0.130  0.030n/a n/a NM = Not Measured *% difference between interior and exterioroxidation surfaces (Batch 4 v Batch 3) = (((outside % oxidation) −(inside % oxidation)) ÷ (outside % oxidation)) × 100

An illustrative process to form a composition comprising discrete carbonnanotubes in a plasticizer is to first select a plurality of discretecarbon nanotubes having an average aspect ratio of from about 10 toabout 500, and an oxidative species content total level from about 1 toabout 15% by weight. Then the discrete carbon nanotubes are suspendedusing shear in water at a nanotube concentration from about 1% to about10% by weight to form the nanotube water slurry. The slurry is thenmixed with at least one plasticizer at a temperature from about 30° C.to about 100° C. for sufficient time that the carbon nanotubes migratefrom the water to the plasticizer to form a water nanotube/plasticizermixer. The mixture can comprise from 70% to about 99.9% water. The bulkof the water is separated from the mixture by filtration, decanting orother means of mechanical separation. The filtered material can containfrom about 50% to about 10% water. The filtered material is then driedat a temperature from about 40° C. to about 120° C. to form an anhydrousnanotube/plasticizer mixture with less than 3% water, most preferablyless than 0.5% water by weight and for some applications 0% water byweight.

Example 5

A concentrate of discrete carbon nanotubes in water with only theexterior wall oxidized as in Example 3 is diluted to a 2% by weight indeionized water. The slurry is heated to 40° C. while stirring with anoverhead stirrer at 400 rpm. For every gram of discrete carbonnanotubes, 4 grams of TOTM (trioctyl trimellitate) from Sigma Aldrich isadded to the stirring mixture. For 4 hours, the mixture is stirred at750 rpm and kept at 40° C. During this time, the oil and discrete carbonnanotubes floats to the top, leaving clear water at the bottom. Whenthis occurs, the water is separated from the TOTM/carbon nanotubemixture by filtration. The TOTM and discrete carbon nanotubes are driedin a forced air convection oven at 70° C. until residual water isremoved. The result is a flowable powder. The concentration of discretecarbon nanotubes is determined by thermogravimetric means and found tobe 20% discrete carbon nanotubes and 80% TOTM.

Example 6

The discrete carbon nanotubes and plasticizer composition of Example 5comprising 20% discrete carbon nanotubes and 80% TOTM (trioctyletrimellitate) is added at concentrations of 2 parts per hundred resin(phr) and 3 parts per hundred resin (phr) to a nitrile rubberformulation (Table 3). The oil concentration of the compounds isadjusted to compensate for the additional oil from the composition ofthis invention. The compound is then cured into plaques for testing.Constrained tear testing is performed using an Instron tensiometer.Constrained tear samples are punched out using a die, making a rectangle1.5 inches by 1 inch by 1 inch with a specimen-centered notch ½ inchlong, sliced perpendicular to the longest dimension. The specimen isgripped equal distance from the notch and pulled by the Instron. Shearstrain and stress is recorded and the area under the stress-strain curvefrom strain zero to the final failure is measured. This area is thetotal tear energy. The results in Table 4 indicate that an increase intear strength is imparted by the discrete carbon nanotubes.

TABLE 3 Ingredient Control 2 phr dCNT 3 phr dCNT Nitrile Rubber (Nipol3640S) 100 100 100 20% dCNT in TOTM 0 10 15 N774 Carbon Black 80 75 75Polyester sebacate plasticizer 15 7 3 (Paraplex G-25) Coumarone IndeneResin 10 10 10 (Cumar P25) Stearic Acid 1 1 1 Zinc Oxide (Kadox 911) 5 55 Antioxidant (Vanox CDPA) 2 2 2 Antioxidant (Santoflex 6PPD) 2 2 2 Highmolecular fatty acid esters 2 2 2 (Struktol WB212) Accelerator DTDM 2 22 Accelerator (Morfax) 2.26 2.26 2.26 Accelerator TMTM 1 1 1

TABLE 4 Description Constrained Tear (psi) Control 482 2 phr dCNT 537 3phr dCNT 574

Example 7

The discrete carbon nanotubes and plasticizer composition of Example 5comprising 20% discrete carbon nanotubes and 80% TOTM (trioctyletrimellitate) is added at concentrations 3 parts per hundred resin (phr)to a nitrile rubber formulation (Table 5). The oil concentration of thecompound is adjusted to compensate for the additional oil from thecomposition of this invention so that all formulations have equivalentoil concentrations. A comparative compound is prepared with carbonnanotubes as received (Flotube C9000, CNano) (Table 5). Carbon blackcontent is adjusted so that the measured hardness is the same for thethree samples. The Shore A hardness is 67 for the control and 67 for the3 phr CNT of this invention and 68 for the 3 phr “As is” carbonnanotubes (C9000). The constrained tear is measured as described inExample 6. The discrete carbon nanotubes and oil composition (dCNT) ofthis invention have higher total tear energy than the entangled carbonnanotubes (C9000) and the control. The tear energy of entangled carbonnanotubes, C9000, is worse than the control. (Table 6)

TABLE 5 3 phr Ingredient Control dCNT 3 phr C9000 Nitrile Rubber (Nipol3640S) 100 100 100 20% dCNT in TOTM 0 15 0 MWCNT as received (C9000,CNano) 0 0 3 N774 Carbon Black 80 75 75 Polyester sebacate plasticizer15 3 15 (Paraplex G-25) Coumarone Indene Resin (Cumar P25) 10 10 10Stearic Acid 1 1 1 Zinc Oxide (Kadox 911) 5 5 5 Antioxidant (Vanox CDPA)2 2 2 Antioxidant (Santoflex 6PPD) 2 2 2 High molecular fatty acidesters 2 2 2 (Struktol WB212) Accelerator DTDM 2 2 2 Accelerator(Morfax) 2.26 2.26 2.26 Accelerator TMTM 1 1 1

TABLE 6 Description Constrained Tear (psi) Control 482 3 phr dCNT 574 3phr C9000 394

It is known to those practiced in the art that the addition of filler toa rubber compound will increase the viscosity of the compound.Unexpectedly, the addition of discrete carbon nanotube and oil mixturefrom Example 7 did not increase the viscosity but instead decreasedviscosity, while the entangled carbon nanotubes of Example 7 (C9000)increased the viscosity. The viscosity is measured using a MooneyRheometer at 125° C. The initial viscosity measured is descriptive ofthe processibility of the compound. The compound containing the discretecarbon nanotubes of this invention and described in Example 7 is foundto be equal to the control while the compound containing the entangledcarbon nanotubes (C9000) is found to be higher than the control (Table7).

TABLE 7 Minimum Mooney Description Viscosity ML (1 + 30) Control 23.1 3phr dCNT 23.1 3 phr C9000 26.6

Disclosed embodiments may also relate to a composition useful fortreating and/or remediating contaminated soil, groundwater and/orwastewater by treating, removing, modifying, sequestering, targetinglabeling, and/or breaking down at least a portion of any dry cleaningcompounds and related compounds such as perchloroethene (PCE),trichloroethene (TCE), 1,2-dichloroethene (DCE), vinyl chloride, and/orethane. Embodiments may also relate to compounds useful for treating,removing, modifying, sequestering, targeting labeling, and/or breakingdown at least a portion of any oils, hazardous or undesirable chemicals,and other contaminants. Disclosed embodiments may comprise a pluralityof discrete carbon nanotubes, wherein the discrete carbon nanotubescomprise an interior and exterior surface. Each surface may comprise aninterior surface oxidized species content and/or an exterior surfaceoxidized species content. Embodiments may also comprise at least onedegradative or otherwise chemically active molecule that is attached oneither the interior or the exterior surface of the plurality of discretecarbon nanotubes. Such embodiments may be used in order to deliver knowndegrative and/or chemically active molecules to the location of anycontaminated soil, groundwater and/or wastewater.

Carbon Nanotubes in Rubbers and Elastomers

The disclosed DLC has been used to incorporate carbon nanotubes intovarious rubbers and rubber formulations. The use of standard rubberprocessing techniques leads to discrete, individualized carbon nanotubesbeing dispersed within the rubber when the disclosed DLC is incorporatedas described. Several DLC formulations were developed and tested withvarious rubber compositions.

Exemplary DLC compositions include MR 1020 DLC which comprises about 20wt % functionalized and discrete CNTs in about 80 wt % TrioctylTrimellitate oil (“TOTM”); MR 1120 DLC which comprises about 20 wt %functionalized and discrete CNTs in about 80 wt % DibutoxyethyoxyethylAdipate oil (“TP-95”); MR 1030 DLC which comprises about 30 wt %functionalized and discrete CNTs in about 70 wt % TOTM oil; and MR 1130DLC which comprises about 30 wt % functionalized and discrete CNTs inabout 70 wt % TP-95 oil. It will be understood that the carbon nanotubecontent within a rubber formulation is the result of both the type andamount of DLC included in the rubber formulation and that theincorporation of the disclosed DLC can increase not only the carbonnanotube content of the rubber formulation but also the associated oilcontent in the rubber formulation.

Nitrile Butadiene Rubber Formulations

Several formulations of nitrile butadiene rubber (NBR) were tested inorder to determine the effects of incorporating carbon nanotubes throughthe disclosed DLC technology. The general composition of these NBRformulations are described in Table 8 below:

TABLE 8 Nitrile Butadiene Rubber Formulations Formulation Carbon BlackCarbon Nanotube Oil Name Content Content Content & Type 72A 80 phr 0 12phr TOTM 72B 75 phr 3 phr CNT 1020 DLC 12 phr TOTM 72D 75 phr 3 phr CNT1120 DLC 12 phr TP-95 72E 75 phr 3 phr CNT 1030 DLC 12 phr TOTM 72F 75phr 3 phr CNT 1130 DLC 12 phr TP-95 72I 75 phr 3 phr CNT 1020 DLC 12 phrTOTM

The resulting rubber formulations were tested using ASTM D395BCompression Set. In general, a lower compression set (“Compression B” or“Cb”) is regarded as being better. The incorporation of carbon nanotubesis shown to provide lower compression set across the board in allsamples. The results are shown in FIG. 10.

Some of these formulations were also subjected to a Constrained TearTest. The Constrained Tear Test subjects a sample to a tensile force asa pull rate of 50 mm/minute. Samples are pre-cut with a 12.7 mm (½″)notch as shown in FIG. 1.

The Constrained Tear Test measures the amount of energy required for atear to propagate entirely through a sample. The results of theConstrained Tear Test as shown in FIG. 11.

In order to ensure dispersion of the carbon nanotubes in a sample of NBRformed using the disclosed DLC technology, a Transmission electronmicroscopy (TEM) images was taken of a sample of NBR formulation 72Bidentified above. As can be seen in FIG. 2, discrete, non-agglomerated,individualized carbon nanotubes are dispersed throughout the sample.

Hydrogenated Nitrile Butadiene Rubber Formulations

Multiple formulations of Hydrogenated Nitrile Butadiene Rubber (“HNBR”)were formed using the MR 1020 DLC composition described above.Additionally, one formulation containing MR 1020 DLC and a controlcontaining no carbon nanotubes were created using both a Banbury mixerand a 2 Roll mill mixer in order to test the effects mixing may have onthe resulting sample. The general composition of these NBR formulationsare described in Tables 9 (Banbury Mixer) and 10 (Roll Mill Mixer)below:

TABLE 9 Hydrogenated Nitrile Butadiene Rubber Formulations using aBanbury Mixer: Sample 1 Sample 2 Sample 3 Sample 4 Banbury Mixer Control2 phr MR 3 phr MR 4 phr MR Zetpol 2020 100 100 100 100 N550 50 50 50 50MR 1020 DLC 0 10 15 20 Kadox 911C 5 5 5 5 Plasthall TOTM 8 0 0 0 StearicAcid 0.5 0.5 0.5 0.5 Naugard 445 1.5 1.5 1.5 1.5 Vanox ZMTI 1 1 1 1Varox 802-40KE 8 8 8 8

TABLE 10 Hydrogenated Nitrile Butadiene Rubber Formulations using a RollMill Mixer Sample 5 Sample 6 Roll Mill Control 2 phr MR Zetpol 2020 100100 N550 50 50 MR 1020 DLC 0 10 Kadox 911C 5 5 Plasthall TOTM 8 0Stearic Acid 0.5 0.5 Naugard 445 1.5 1.5 Vanox ZMTI 1 1 Varox 802-40KE 88

It will be understood that the ingredients in the formulations describedabove are exemplary. An ordinary artisan will understand that similaringredients may be obtained from other companies under different tradenames but the chemical composition will be substantially similar.

A series of performance tests were performed on HNBR formulations 1-6described above. The results of these tests show that adding carbonnanotubes to the rubber formulation increases tear resistance. Detailsof the test results are shown in Table 11 below:

TABLE 11 HNBR Testing Results. N085-033- 1 2 3 4 5 6 Mooney StressRelaxation, ML(1 + 4 + 4) @100° C. Temperature, (° C.) 100 100 100 100100 100 Final Viscosity 103.5 102.4 99.5 95.3 92.2 103.1 Time to 80%Decay 4.05 4.06 4.06 4.06 4.04 4.05 Slope −0.56 −0.51 −0.49 −0.47 −0.59−0.54 Viscosity @ 4.5 mins. 5.8 6.6 6.6 6.8 4.1 6.0 Mooney Scorch ML @100° C., ML(1 + 30) @ 125° C. Minimum Viscosity 64.3 64.3 62.9 59.8 55.764.3 T5, (min) 25.2 26.2 28.7 >30 27.5 25.1 T35,(min) >30 >30 >30 >30 >30 >30 MDR-2000 Rheometer, 100 pphm, 30/180° C.,100 cpm, 0.5° arc ML, (lbf · in) 1.4 1.5 1.5 1.5 1.2 1.5 MH, (lbf · in)25.3 25.4 23.4 22.4 24.0 24.0 Ts2, (min) 0.5 0.5 0.5 0.5 0.5 0.5 T′90,(min) 4.2 4.1 4.1 4.1 4.1 4.1 T′90 Tan Delta 0.038 0.045 0.050 0.0570.043 0.049 Cure Time, (min) 11 11 11 11 11 11 Original Vulcanized,Hardness A, (pts) 74 75 75 74 75 74 Modulus @ 10%, (psi) 130 129 137 112123 135 Modulus @ 25%, (psi) 222 245 243 221 210 241 Modulus @ 50%,(psi) 410 457 438 406 372 424 Modulus @ 100%, (psi) 1157 1288 1239 11331038 1162 Modulus @ 200%, (psi) 3315 3366 3220 2962 3070 3202 Tensile,(psi) 4236 4105 4115 3806 4148 4243 Elongation, (%) 254 243 262 261 266268 Tear Strength, Die C, Tear Strength, (ppi) 321 331 336 334 322 343

Graphical Representation of the results of the Die C Tear Strength testand the Constrained Tear Test of the HNBR samples 1-6 are shown in FIGS.12 and 13. The Die C test is also known as ASTM D-624 and generallymeasures the force per unit thickness required to initiate a rupture ortear. These results show that the incorporation of carbon nanotubes intorubber formulations increases tear toughness, both in the Die C andConstrained Tear tests. These results also show that incorporation ofcarbon nanotubes softens, or maintains rubber seal hardness without aloss of physical properties.

TABLE 12 Constrained Tear Data for HNBR Samples Sample Area under curveStd. Dev. 1 61 5 2 75 5 3 98 8 4 95 4 5 64 8 6 85 8

TABLE 13 Comparison of the Constrained Tear Test results Comparison %Improvement 1 -> 2 22% 1 -> 3 60% 1 -> 4 55% 5 -> 6 34%

Transmission Electron Microscopy (“TEM”) images were taken of HNBRsamples with and without carbon nanotubes incorporated. The images areshown in FIGS. 3, 4, and 5.

As can be seen by comparison of FIGS. 3 and 5, the carbon nanotubesdisperse approximately equivalently in the rubber formulation regardlessof whether or not the formulation contains carbon black.

Additional testing of various HNBR formulations comprising carbonnanotubes from DLC as well as dry-carbon nanotubes are disclosed below.The HNBR formulations and testing results are detailed below. In thecharts below, “CNT OC” indicates CNANO C9000 tangled carbon nanotubes ina dry liquid concentrate and “DRY CNT” indicates as manufactured CNANOC9000 tangled tubes which are not formed into a DLC.

TABLE 14a Carbon Nanotubes in HNBR Formulations HNBR- HNBR- HNBR- HNBR-HNBR- HNBR- HNBR- HNBR- FA-01 FA-02 FA-03 FA-04 FA-07 FA-08 FA-09 FA-10Material PHR PHR PHR PHR PHR PHR PHR PHR HNBR- Zetpol 2020 100.00 100.00100.00 100.00 100.00 100.00 100.00 100.00 N550 CB 50.00 50.00 50.0050.00 50.00 50.00 50.00 50.00 MR 1020 DLC 7.07 7.07 Plasthall TOTM 8.005.57 2.43 2.20 8.00 5.57 CNT OC 7.30 7.30 Dry CNT 1.50 1.50 Stearic Acid0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 Zinc Oxide 5.00 5.00 5.00 5.005.00 5.00 5.00 5.00 CDPA 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 ZMTI1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Varox 802 40-KE 8.00 8.00 8.008.00 8.00 8.00 8.00 8.00

TABLE 14b Rheological curing data of carbon nanotubes in HNBRformulations. ODR (0.5° Arc) 20 Min/180° C., HNBR- HNBR- HNBR- HNBR-HNBR- HNBR- HNBR- HNBR- FA-01 FA-02 FA-03 FA-04 FA-07 FA-08 FA-09 FA-10ML, (lbf · in) 7.06 7.88 7.83 8.54 8.13 8.13 7.87 7.86 MH, (lbf · in)59.87 61.1 57.21 61.19 60.83 61.45 60.46 60.5 MH − ML (lbf · in) 52.8153.22 49.38 52.65 52.70 53.32 52.59 52.64 Ts1, (min) 01:03.3 01:03.7 1:04 01:03.0 01:04.9 01:04.2 01:03.3 01:01.4 T′90, (min) 05:57.605:51.0 05:54.2 05:12.2 05:18.0 05:13.2 05:59.4 05:54.6 Cure time (T90 +2) min 07:57.6 07:51.0 07:54.2 07:12.2 07:18.0 07:13.2 07:59.4 07:54.6

TABLE 15a Basic Physical Properties- Tensile, Elongation, Modulus - MeanData Mean Total Total Tensile stress Elongation Tensile stress Tensilestress Oil MR/CNT at Break at Break Modulus @ 100% @ 200% ContentContent Sample ID (psi) (%) (psi) (psi) (psi) 8 0 HNBR-FA-01 3,985 2502,108 1,375 3,301 5.57 0 HNBR-FA-02 3,895 240 2,123 1,376 3,213 MR-DLC 81.5 HNBR-FA-03 3,911 260 2,074 1,336 3,188 MR-DLC 5.57 1.5 HNBR-FA-043,839 250 2,043 1,369 3,239 CNT-OC 8 1.5 HNBR-FA-07 3,612 220 2,1161,408 3,310 CNT-OC 5.8 1.5 HNBR-FA-08 3,838 220 2,231 1,582 3,556Dry-CNT 8 1.5 HNBR-FA-09 3,801 200 2,409 1,690 3,633 Dry-CNT 5.57 1.5HNBR-FA-10 3,941 190 2,811 1,989 4,034

TABLE 15b Basic Physical Properties- Tensile, Elongation, Modulus -Standard Deviation Data Standard Deviation Total Total Tensile stressElongation Tensile stress Tensile stress Oil MR/CNT at Break at BreakModulus @ 100% @ 200% Content Content Sample ID (psi) (%) (psi) (psi)(psi) 8 0 HNBR-FA-01 112 10 80 85 115 5.57 0 HNBR-FA-02 251 30 234 216225 MR-DLC 8 1.5 HNBR-FA-03 129 10 47 82 91 MR-DLC 5.57 1.5 HNBR-FA-04141 20 72 71 125 CNT-OC 8 1.5 HNBR-FA-07 130 10 114 103 140 CNT-OC 5.81.5 HNBR-FA-08 143 20 106 107 126 Dry-CNT 8 1.5 HNBR-FA-09 78 10 145 132108 Dry-CNT 5.57 1.5 HNBR-FA-10 101 20 261 192 25

TABLE 16a Constrained Tear Test Mean Data Mean Total Total Tensilestress Elongation Oil MR/CNT at Break at Break width Thickness ContentContent Sample ID (psi) (%) (in) (in) AUCi (ksi) AUCf (psi) 8 0HNBR-FA-01 306 28 0.50 0.09 0.07 71 5.57 0 HNBR-FA-02 333 30 0.50 0.090.08 81 MR-DLC 8 1.5 HNBR-FA-03 361 33 0.50 0.10 0.11 106 MR-DLC 5.571.5 HNBR-FA-04 385 33 0.50 0.09 0.09 99 CNT-OC 8 1.5 HNBR-FA-07 332 300.50 0.09 0.08 86 CNT-OC 5.8 1.5 HNBR-FA-08 367 32 0.50 0.08 0.10 100Dry-CNT 8 1.5 HNBR-FA-09 358 32 0.50 0.09 0.09 94 Dry-CNT 5.57 1.5HNBR-FA-10 374 33 0.50 0.09 0.10 105

TABLE 16b Constrained Tear Test Standard Deviation Data S.D. Total TotalTensile stress Elongation Oil MR/CNT at Break at Break Content ContentSample ID (psi) (%) AUCi (ksi) AUCf (psi) 8 0 HNBR-FA-01 10 1 0.01 45.57 0 HNBR-FA-02 18 2 0.00 5 MR-DLC 8 1.5 HNBR-FA-03 19 1 0.01 7 MR-DLC5.57 1.5 HNBR-FA-04 44 4 0.01 13 CNT-OC 8 1.5 HNBR-FA-07 16 1 0.01 8CNT-OC 5.8 1.5 HNBR-FA-08 11 1 0.01 5 Dry-CNT 8 1.5 HNBR-FA-09 8 1 0.001 Dry-CNT 5.57 1.5 HNBR-FA-10 18 2 0.01 8

TABLE 17a Die C Tear Test - Mean Data Mean Total Total Maximum Max Load/Max Load/ Energy at Oil MR/CNT Load Thickness Thickness Thickness AUCMaximum Load Content Content Sample ID (N) (N/mm) (kN/mm) (mm) (J) (J) 80 HNBR-FA-01 63 25336 25.3 2.5 0.9 0.4 5.57 0 HNBR-FA-02 57 26032 26.02.2 0.8 0.4 MR-DLC 8 1.5 HNBR-FA-03 65 28555 28.6 2.3 1.0 0.5 MR-DLC5.57 1.5 HNBR-FA-04 58 28209 28.2 2.1 0.8 0.4 CNT-OC 8 1.5 HNBR-FA-07 6427898 27.9 2.3 0.9 0.5 CNT-OC 5.8 1.5 HNBR-FA-08 57 26543 26.5 2.1 0.80.4 Dry-CNT 8 1.5 HNBR-FA-09 70 29696 29.7 2.4 1.1 0.5 Dry-CNT 5.57 1.5HNBR-FA-10 67 28589 28.6 2.3 1.0 0.5

TABLE 17b Die C Tear Test - Mean Data Standard Deviation Total TotalMaximum Max Load/ Max Load/ Energy at Oil MR/CNT Load ThicknessThickness AUC Maximum Load Content Content Sample ID (N) (N/mm) (kN/mm)(J) (J) 8 0 HNBR-FA-01 4.0 1231 1.2 0.1 0.0 5.57 0 HNBR-FA-02 3.0 12741.3 0.1 0.0 MR-DLC 8 1.5 HNBR-FA-03 4.2 1907 1.9 0.1 0.1 MR-DLC 5.57 1.5HNBR-FA-04 4.3 1579 1.6 0.1 0.0 CNT-OC 8 1.5 HNBR-FA-07 4.9 1926 1.9 0.10.1 CNT-OC 5.8 1.5 HNBR-FA-08 4.9 1264 1.3 0.1 0.0 Dry-CNT 8 1.5HNBR-FA-09 5.2 2260 2.3 0.2 0.1 Dry-CNT 5.57 1.5 HNBR-FA-10 7.7 2685 2.70.2 0.1

Dispersion of MR as Compared to Dispersion of CNTs Via DLC

Transmission Electron Microscopy (“TEM”) images were taken of HNBRsamples with MR and CNTs dispersed via DLC as well as HNBR sample withdry CNTs. The images are shown in FIGS. 6, 7, 8 a and 8 b.

As can be seen in FIGS. 6-8 b, the dispersion of dry CNTs in rubberformulations is not similar, and is in fact entirely distinct from thedispersion of both MR and CNTs dispersed via DLC. When dry CNTs areincorporated into rubber formulations, dispersion is uneven resulting inportions of rubber contain high CNT concentration as well as voids withrelatively few if any CNTs present. This can lead to premature failureof the material during stress/strain events. The non-homogeneous loadingof dry-CNTs leads to unpredictable and variable performance of theresulting rubber.

Cut and Chip Enhancements in Natural Rubber Latex

Several formulations of rubber were tested in order to determine theeffects of incorporating carbon nanotubes on cut and chip test resultsusing coagulated natural rubber latex as a delivery mechanism. Thesenatural rubber (“NR”) blended with polybutadiene rubber (“BR”)formulations are generally similar to the rubber formulations used forcommercial truck tread and show large improvements in cut and chiptesting when 2.5 and 3.5 phr of functionalized and discrete CNT, alsoknown as MR, are incorporated into the rubber formulation. The generalcomposition of these NR/BR formulations are described in the tablebelow.

TABLE 18 NR Formulations with for Cut and Chip Testing. IngredientsControl +2.5 phr MR +3.5 phr MR CV60 Natural Rubber 80 80 80 BR 1207 2020 20 CB N220 45 45 45

The cut and chip test has been developed by B.F. Goodrich and isgenerally depicted in FIG. 9.

The cut and chip test indicates how much weight is lost from theoriginal sample as a result of the test. Less weight loss is generallyindicative of higher durability and resistance to damage. The results ofthe cut and chip testing are shown in FIG. 14.

TABLE 19 Cut and Chip test data. Compound Identification Control 3.5 phrCNT 2.5 phr CNT Weight Loss (grams) Sample 1 1.6783 0.3923 0.7050 Sample2 0.9116 0.6678 0.4701 Average 1.2950 0.5301 0.5876 Diameter Loss(inches) Sample 1 0.13 0.01 0.04 Sample 2 0.07 0.02 0.02 Average 0.100.02 0.03

High Shear v. Bundled v. Mixture of High Shear and Bundled Example

Three preparations of MWCNT (C9000, CNano Technologies) in water areanalyzed for particle size distribution. Size distribution is measuredusing laser diffraction instrumentation (Microtrac S3500, Microtrac).One skilled in the art will understand that laser diffraction methodsfor particle size assumes spherical to near spherical shape and particlesize of flexible, high aspect ratio particles, such as MWCNT, is arelative measurement influenced by the length and is not the true lengthof the MWCNT. One preparation is 1% by weight bundled MWCNT in waterthat are not subjected to intense shear nor any oxidation and isessentially 100% bundled tubes. The second preparation is 1% by weightoxidized, discrete MWCNT in water prepared per example 3. This materialis subjected to 10 minutes of high shear in a rotor stator having a gapof 0.5 mm. Then it is subjected to high shear devices with animpingement of 10 microns and pressure of 8000 psi. The total energy is4.96×10⁸ J/kg. The discrete feature is confirmed by scanning electronmicroscopy. The third preparation is a mixture of discrete and bundledMWCNT as a 1% by weight concentration in water and is made by subjectingMWCNT bundles to no oxidation. This preparation is subjected to 10minutes of high shear in a rotor stator having a gap of 0.5 mm. Then itis subjected to a high shear device with an impingement gap of 10microns and pressure of 8000 psi. The total energy is 1.10×10⁸ J/kg.FIG. 15 shows the distinct difference between fully bundled and discreteMWCNT and the substantial overlap of the mixture with the discrete and asmall overlap of the mixture with the bundles. Using the percentile datain Table 20 below, 95% of the discrete MWCNT are less than 25.3 microns.Using this as the limit of the size of discrete tubes, the percentage ofdiscrete MWCNT in the mixture is extrapolated to be 56% discrete.

TABLE 20 Mixture of Bundled and Bundled Discrete Discrete MWCNT MWCNTMWCNT Percentile [micron] [micron] [micron] 10 123.8 13 7.2 20 287.216.2 8.9 30 437.2 18.8 10.2 40 754.3 21.2 11.4 50 821.2 23.6 12.7 60827.6 26.3 14.1 70 919.6 29.5 15.7 80 973.2 33.7 17.9 90 1061 41.2 21.595 1147 49.7 25.3

The data of Table 20 shows that mixtures of bundled and discreteparticles may be employed in the applications of the disclosedinventions.

Mixtures like those of Table 20 may comprise tangled carbon nanotubesand discrete carbon nanotubes. Generally, the average particle size ofthe carbon nanotubes in the mixture may be at least about 15 microns, orat least about 20 microns, or at least about 25 microns, or at leastabout 35 microns, or at least about 40 microns, up to about 85 microns,or up to about 75 microns, or up to about 65 microns, or up to about 60microns. The amount of tangled carbon nanotubes in the mixture may vary.Typically, the amount of tangled carbon nanotubes in the mixture may beat least about 20, or at least about 25, or at least abut 30, or atleast about 35, or at least about 40 percent based on the total weightof carbon nanotubes in the mixture. On the other hand the amount oftangled carbon nanotubes in the mixture may be up to about 80, or up toabout 70, or up to about 60, or up to about 55, or up to about 49percent based on the total weight of carbon nanotubes in the mixture.Generally, the average particle size of the discrete carbon nanotubes inthe mixture is less than those of the tangled carbon nanotubes. In somecases the average particle size of the discrete carbon nanotubes in themixture may be at least about 15 microns or at least about 20 microns upto about 35 microns or up to about 30 microns. In some case more thanabout 80%, or more than about 90%, of the discrete carbon nanotubes inthe mixture have a particle size of less than about 30 microns.

The discrete and tangled carbon nanotubes mixture may be derived fromcommercially available multi-walled carbon nanotubes with little or nooxidized species content. That is, the total amount of oxidized speciescontent may be less than about 1 percent, or less than about 0.6percent, or less than about 0.4 percent relative to total carbonnanotube weight.

The mixture of discrete and tangled carbon nanotubes like those of Table20 may include additional ingredients. Such ingredients include, forexample, a processing oil such as those selected from the groupconsisting of Trioctyl Trimellitate (TOTM), Dioctyl Adipate (DOA),Dibutoxyethoxyethyl adipate, castor oil, naphthenic oil, residualaromatic extract oil (RAE), treated distillate aromatic extracted oil(TDAE), aromatic oils, paraffinic oils, carnauba wax, curing co-agents,natural waxes, synthetic waxes, and peroxide curatives. Other potentialingredients include rubber compounds, epoxy resins, and polyurethanes.

Generally, the process to obtain the mixture comprising tangled carbonnanotubes and discrete carbon nanotubes like that of Table 20 usuallybegins with preparing a 1-4% by weight slurry of bundled, i.e., tangled,carbon nanotubes in water. The mixture is then subjected to a firstintense shear device and then optionally subjected to a second intenseshear device. The slurry may be processed 1-8 passes through the secondintense shear device to yield the desired particle size distribution.The shear devices may include, for example, a rotor stator orhomgenizers like a manton gaulin. Thus, an aqueous mixture of entanglednanotubes is sheared at conditions such that the result is a mixturecomprising tangled carbon nanotubes and discrete carbon nanotubes,wherein the average particle size of the carbon nanotubes in the mixtureis from about 15 to about 85 microns and wherein the amount of tangledcarbon nanotubes is from about 20 to about 80 percent based on the totalweight of carbon nanotubes in the mixture. Specific shearing conditionsmay be varied to make the desired size and relative amounts of tangledand discrete carbon nanotubes. Generally, the shearing conditions maycomprise a total energy of from about 1×10⁷ Joules/kg to 3×10⁸Joules/kg.

Applications of the Disclosed Inventions

As discussed above, the incorporation of carbon nanotubes into rubberformulations can enhance the physical properties of the rubber, allowingfor greater resistance to being cut, chipped, or generally abraded.Rubber formulations incorporated carbon nanotubes may be useful inmining and milling operations. Durable rubber coatings, also sometimesknown as sacrificial rubber coatings, can be applied to exposed orworking surfaces in mixing devices, rock crushers, and a wide array ofother surfaces that are exposed to harsh operating conditions. Otherapplications include those not necessarily exposed to operatingconditions or elements, and include wear resistant linings, such as pipeliners containing abrasive fluids, such a cement or rock slurry, andconveyor belts.

Abrasion resistant rubber coatings are useful for use creating tires andtreads with increased durability and longer operating life. Tires forpassenger as well as commercial vehicles and airplanes are envisioned aswell as tires for large equipment such as excavators, dump-trucks,agricultural equipment, military equipment, and other heavy machinery.

Abrasion resistant rubber may be applied as a coating for protecting theunderlying surfaces from both physical damage as well as chemical oroxidative damage. Such applications include coating the hull of boatsand ships, thereby insulating them from potential chemical oxidants suchas salt water as well as protecting the hull surface from impacts whendocking, mooring, or general wear-and-tear. These coatings could alsO beused to line both the interior and exterior of reaction vessels whichmay be in contact with harsh or otherwise reactive chemical agentsand/or exposed to physical damage. Protective rubber coatings could beapplied to the surfaces of gas cylinders and other pressure vessels inorder to prevent damage when they are moved, loaded, unloaded, ortransported and may be exposed to contact with transportation equipmentas well as other similar vessels. Such coatings could be used forcoating truck beds including passenger vehicle pick-up trucks anddump-truck containers as well as the interior of shipping and truckingcontainers, fork lift and hand-truck components, and other surfacesroutinely exposed to abrasion or other harsh conditions.

Abrasion resistant rubber formulations may be tailored to includetexture additives in order to create highly durable non-slip coatingswhich could be used to surfaces which may become wet or slippery inorder to protect customers, passengers, employees, and other personnel.Such uses include coating stairs, platforms, and walkways onconstruction sites, drilling rigs, mining equipment, boats and ships,factories, manufacturing plants, lumber mills, and any environment whereprecautions against slipping should be taken.

Durable rubber formulations may also be used to manufacture rubbercomponents with increased life span. This includes at least rubbergaskets and seals for use in drilling, mining, construction, mixing, andmany other industrial applications. Such gaskets and seals could also beuseful in engines, motors, and other high-pressure applications in whichlonger life, and therefore less frequent maintenance of the gaskets andseals is advantageous.

High durability rubber could also be used for long life vibration andsound dampening components. These components could include bushings forpassenger and commercial vehicles. Heavy equipment and airplanes may seeparticular advantage as the bushings and dampening components in suchapplications are typically exposed to greater than normal forces anddemanding operating conditions.

It will be appreciated that the carbon nanotubes mentioned in thisdisclosure may be single, double, or multi-walled nanotubes. Thenanotubes discussed may be oxidized on the interior and/or exteriorsurface either separately or in combination. The nanotubes may haveclosed or open ends and may have other molecules attached to theinterior or exterior surfaces through covalent, ionic, Van der Waals,electromagnetic or any form of bond.

It will also be appreciated that while experimental data has beenpresented for exemplary purposes, the specific rubbers disclosed are notintended to be limiting. It is anticipated that the incorporation ofcarbon nanotubes, as disclosed throughout, will produce similar resultsin a wide array of rubbers, elastomers, polymers, and similar materials.

Embodiments of the Invention

1. A composition of a dry liquid concentrate comprising a plurality oftangled carbon nanotubes and processing oil, wherein the nanotubescomprise from about 5% to about 50% of the composition by weight.

2. The composition of embodiment 1, wherein the nanotubes comprise fromabout 10% to about 40% of the composition by weight.

3. The composition of embodiment 1, wherein the nanotubes comprise fromabout 15% to about 30% of the composition by weight.

4. The composition of embodiment 1, wherein the rubber processing oilcomprising trioctyl trimellitate oil.

5. The composition of embodiment 1, wherein the rubber processing oilcomprising dibutoxyethyoxyethyl adipate oil.

6. The composition of embodiment 1, wherein the rubber processing oilcomprises naphthenic oil.

7. The composition of embodiment 1, wherein the carbon nanotubescomprise multi-wall carbon nanotubes.

8. The composition of embodiment 1 further comprising at least onerubber compound, thereby forming a discrete carbon nanotube, oil, rubbercomposition.

9. The composition of embodiment 1, wherein the tangled carbon nanotubescomprise discrete carbon nanotubes, wherein the discrete carbonnanotubes comprise an interior surface and an exterior surface, andwherein the interior surface comprises an oxidized species content fromabout 0.01 to less than about 1 percent relative to carbon nanotubeweight, and the exterior surface comprises an oxidized species contentmore than about 1 to about 3 percent relative to carbon nanotube weight.

10. The composition of embodiment 9 further comprising at least onerubber compound, thereby forming an oxidized discrete carbon nanotube,oil, rubber composition.

11. A process for dispersing carbon nanotubes into a polymer, comprisingthe steps of

-   -   (a) soaking and/or agitating entangled carbon nanotubes in a        first medium comprising at least one aqueous solution at a        temperature above about 25° C.,    -   (b) phase transferring the entangled carbon nanotubes in the        first medium to a second medium comprising an oil solution,    -   (c) mixing the entangled carbon nanotubes in the second medium        at a selected shear condition and at a temperature above about        25° C.,    -   (d) removing excess or separated aqueous solution from the        second medium, and    -   (e) mixing using shear conditions higher than that used in (c)        in compounding equipment to form a final polymer/dispersed        carbon nanotubes formulation.

12. The process of embodiment 11, wherein the steps (a) through (e) aresequential.

13. The process of embodiment 11, wherein the tangled carbon nanotubesin step (a) are commercially available and have not been physically orchemically altered.

14. The process of embodiment 11, wherein the temperature in step (a) ispreferably between from about 35° C. to about 100° C., and especiallyfrom about 55° C. to about 75° C.

15. The process of embodiment 11, wherein the agitating in step (a) isperformed using a high shear mixer, with a shear rate from about 10⁶ toabout 10⁸ Joules/m³.

16. The process of embodiment 11, wherein the phase transferring to thesecond medium in step (b) takes place on a shear-dependent time scale,such that higher shear corresponds to a shorter process time, with shearrates ranging from about 10⁶ to 10⁸ Joules/m³.

17. The process of embodiment 11, wherein the phase transferring fromthe first medium to the second medium in step (b) occurs at atemperature from about 35° C. to about 100° C., preferably from about55° C. to about 75° C.

18. The process of embodiment 11, wherein the second medium in step (b)comprises a processing aid and/or rubber compounding ingredient.

19. The process of embodiment 18 wherein the processing aid and/oringredient is selected from the group consisting of TrioctylTrimellitate (TOTM), Dioctyl Adipate (DOA), Dibutoxyethoxyethyl adipate,castor oil, naphthenic oil, residual aromatic extract oil (RAE), treateddistillate aromatic extracted oil (TDAE), aromatic oils, paraffinicoils, carnauba wax, curing co-agents, natural waxes, synthetic waxes,and peroxide curatives.

20. The process of embodiment 11, wherein the polymer in step (d) isselected from the group consisting of thermoplastics, elastomericpolymers, synthetic rubbers, natural rubbers, hydrocarbon-basedpolymers, and blends thereof.

21. The process of embodiment 11, wherein the polymer in step (a)comprises a compound selected from the group consisting of naturalrubber, styrene butadiene rubber, nitrile butadiene rubber,polybutadiene rubber, ethylene propylene diene rubber, hydrogenatednitrile butadiene rubber, silicone rubber, polyurethane rubber,fluorinated polymers, and perfluorinated polymers.

22. The process of embodiment 11, wherein the final polymer formulationin step (d) has a filler content higher than 15 parts per hundredrubber, preferably from about 20 to about 90 parts per hundred rubber.

23. The process of embodiment 11, wherein the high shear compoundingequipment in step (d) exerts 10⁶ to 10⁸ Joules/m³ shear force on thecompound

24. The process of embodiment 11, wherein the high shear compoundingequipment is selected from the group consisting of a tangential typemixer, intermeshing type mixer, 2 roll mill, calendaring mill, and ascrew type extruder, or combination thereof.

25. The process of embodiment 11 wherein the entangled carbon nanotubesin step (a) are present in the first medium at a concentration of fromabout 1 to about 3 percent by weight of the carbon nanotubes.

26. The process of embodiment 11 wherein the entangled carbon nanotubesin step (b) are present in the second medium at a concentration of fromabout 10 to about 30 percent by weight of the carbon nanotubes.

27. The process of embodiment 11 wherein the dispersed carbon nanotubesin step (d) are present in the final polymer/dispersed carbon nanotubesformulation at a concentration of from about 0.25 to about 0.5 percentby weight of the carbon nanotubes.

28. The process of embodiment 27 wherein the dispersed carbon nanotubesin the polymer/dispersed carbon nanotube formulation are homogeneouslydispersed.

29. The process of embodiment 28 wherein the dispersed carbon nanotubesin the polymer/dispersed carbon nanotube formulation are discrete.

30. The process of embodiment 11 wherein the tangled carbon nanotubes instep (a) are soaking and/or agitating during a time period of from about5 minutes to about 3 hours.

31. A process of forming an abrasion resistant rubber/carbon nanotubescomposition, comprising the steps of

-   -   (a) soaking and/or agitating entangled carbon nanotubes in a        first medium comprising at least one aqueous solution at a        temperature above about 25° C.,    -   (b) phase transferring the entangled carbon nanotubes to a        second medium,    -   (c) mixing at a selected shear condition and at a temperature        above about 25° C., (d) removing excess or separated aqueous        solution,    -   (e) drying the oil-nanotube solution to form a dry-liquid        concentrate, and,    -   (f) dispersing the dry liquid concentrate into at least one        rubber to form a final abrasion resistant rubber/dispersed        carbon nanotubes formulation.

32. The process of embodiment 31 wherein step (f) is accomplished bymixing under shear conditions higher than that used in (c).

We claim:
 1. A mixture comprising tangled carbon nanotubes and discretecarbon nanotubes, wherein the average particle size of the carbonnanotubes in the mixture is from about 15 to about 85 microns andwherein the amount of tangled carbon nanotubes is from about 20 to about80 percent based on the total weight of carbon nanotubes in the mixture,wherein an interior surface oxidized species content of the discretecarbon nanotubes is from zero to about 3 weight percent relative tocarbon nanotube weight and wherein an exterior surface oxidized speciescontent of the discrete carbon nanotubes is from about 1 to about 6weight percent relative to carbon nanotube weight.
 2. The mixture ofclaim 1, wherein the amount of tangled carbon nanotubes is from about 25to about 70 percent based on the total weight of carbon nanotubes in themixture.
 3. The mixture of claim 1, wherein the amount of tangled carbonnanotubes is from about 30 to about 60 percent based on the total weightof carbon nanotubes in the mixture.
 4. The mixture of claim 1, whereinthe amount of tangled carbon nanotubes is from about 35 to about 55percent based on the total weight of carbon nanotubes in the mixture. 5.The mixture of claim 1, wherein the amount of tangled carbon nanotubesis from about 40 to about 49 percent based on the total weight of carbonnanotubes in the mixture.
 6. The mixture of claim 1, wherein the averageparticle size of the carbon nanotubes in the mixture is from about 25 toabout 75 microns.
 7. The mixture of claim 1, wherein the averageparticle size of the carbon nanotubes in the mixture is from about 35 toabout 65 microns.
 8. The mixture of claim 1, wherein the averageparticle size of the carbon nanotubes in the mixture is from about 40 toabout 60 microns.
 9. The mixture of claim 1, wherein the averageparticle size of the discrete carbon nanotubes in the mixture is fromabout 15 to about 35 microns.
 10. The mixture of claim 1, wherein theaverage particle size of the discrete carbon nanotubes in the mixture isfrom about 20 to about 30 microns.
 11. The mixture of claim 1, whereinmore than about 80% of the discrete carbon nanotubes in the mixture havea particle size of less than about 30 microns.
 12. The mixture of claim1, wherein more than about 90% of the discrete carbon nanotubes in themixture have a particle size of less than about 30 microns.
 13. Themixture of claim 1 further comprising processing oil.
 14. The mixture ofclaim 1 further comprising an additional ingredient selected from thegroup consisting of trioctyl trimellitate, dioctyl adipate,dibutoxyethoxy ethyl adipate, castor oil, naphthenic oil, residualaromatic extract oil, treated distillate aromatic extracted oil,aromatic oils, paraffinic oils, carnauba wax, curing co-agents, naturalwaxes, synthetic waxes, and peroxide curatives.
 15. The mixture of claim1 wherein the carbon nanotubes comprise multi-wall carbon nanotubes. 16.The mixture of claim 1 further comprising at least one rubber compound.17. The mixture of claim 1 further comprising an epoxy resin.
 18. Themixture of claim 1 further comprising a polyurethane.